• 한국산업융합학회 논문집
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• 제1권2호
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• pp.13-19
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• 1998

A computer simulation program for the design of furnace witjin pakaged water-tube boilres is developed and the developed computer program is successfully applied to design the furnace for packaged water-tube boiler. The model by experiment and the model by Hottel are used to predict the exit gas temperature of furnace. The result by two models is discussed and is shown that in the case of constant cross section in furnace, the result is same but in changing the configuration of cross section, the difference by two models is not small.

• 한국산업융합학회 논문집
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• 제2권2호
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• pp.3-10
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• 1999

Recently, It is proceeding the project of offshore structures in the many contury. A hybrid boundary-integral method is developed for computing wave forces on floating bodies. In this method, using the cylindric boundary for deviding elements, it is convenient to analysis but is difficult to apply to the rectangular or slender bodies. Thus, in this paper, I propose the new method by using the fictitious vertical cylinder of arbitary cross-section and shows results of the numerical analysis for testing.

• Structural Engineering and Mechanics
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• 제43권2호
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• pp.147-161
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• 2012

This paper presents a curvature method for analysis of beam-columns with different materials and arbitrary cross-section shapes and subjected to combined biaxial moments and axial load. Both material and geometric nonlinearities (the p-delta effect in this case) were incorporated. The proposed method considers biaxial curvatures and uniform normal strains of discrete cross-sections of beam-columns as basic unknowns, and seeks for a solution of the column deflection curve that satisfies force equilibrium conditions. A piecewise representation of the beam-column deflection curve is constructed based on the curvatures and angles of rotation of the segmented cross-sections. The resulting bending moments were evaluated based on the deformed column shape and the axial load. The moment curvature relationship and the beam-column deflection calculation are presented in matrix form and the Newton-Raphson method is employed to ensure fast and stable convergence. Comparison with results of analytic solutions and eccentric compression tests of wood beam-columns implies that this method is reliable and effective for beam-columns subjected to eccentric compression load, lateral bracings and complex boundary conditions.

• 융복합기술연구소 논문집
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• 제3권2호
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• pp.17-21
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• 2013

Hot cross wedge rolling process as an incremental forming has many advantages such as the material usage, the short process time, the automatic equipment line and the low forming load. However, it occurs some defects such as the surface groove, the axis warping and the Mannesmann hole. In this paper, the defect of the Mannesmann hole was carried out. Finite element analysis was utilized to reveal the stress distribution, the rotation of the specimen and the change of section profile. Cross wedge rolling experiment was also conducted on the generation of the Mannesmann hole. It was demonstrated according to the spreading angle with respect to the various types of material. In the view point of metal flow, the smaller forming angle and the larger spreading angle increase opportunities of the defect hole generations.

• Journal of the Korean Physical Society
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• 제73권9호
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• pp.1230-1239
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• 2018

We derive a factorization theorem for the jet mass distribution with a given $p^J_T$ for the inclusive production, where $p^J_T$ is a large jet transverse momentum. Considering the small jet radius limit ($R{\ll}1$), we factorize the scattering cross section into a partonic cross section, the fragmentation function to a jet, and the jet mass distribution function. The decoupled jet mass distributions for quark and gluon jets are well-normalized and scale invariant, and they can be extracted from the ratio of two scattering cross sections such as $d{\sigma}/(dp^J_TdM^2_J)$ and $d{\sigma}/dp^J_T $. When $M_J{\sim}p^J_TR$, the perturbative series expansion for the jet mass distributions works well. As the jet mass becomes small, large logarithms of $M_J/(p^J_TR)$ appear, and they can be systematically resummed through a more refined factorization theorem for the jet mass distribution.

• 융복합기술연구소 논문집
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• 제1권1호
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• pp.24-28
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• 2011

The purposes of this study are predictions of the changes in the section geometry and determination of the initial cross section so that opposite side in height direction is exactly parallel after coiling process. Finite element analysis is carried out for the calculation of the sectional changes for mold spring item. Analysis results reveal that the slope of the top and bottom sides varies in the range of 5 to 8 degrees and the amount depends on the dimension of the outer diameter. The slopes of the sides should be defined first among design variables.

• 한국지반신소재학회논문집
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• 제17권1호
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• pp.111-118
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• 2018

단층 등 취약지반 조건에서의 터널굴착 시 터널천단 및 측벽변위의 억제를 목적으로 하는 각부보강공이 일반적으로 적용되고 있으며, 터널 단면증가 변화율에 따른 각부보강공 설치각도 및 길이를 고려한 지보안전성 확인을 위한 주요 인자로서 내공변위 천단침하 각부침하 각부축력 등의 여러 응력변위 특성 변수들이 있다. 이러한 굴착중 안전성확인을 위한 변수들에 대한 검토 결과, 우각부 침하영향성이 단면증가율 보다 더 큰 변위경향을 보이는 가장 중요한 중점관리 지배요소로 분석되었으며, 터널단면 증가 변화율에 대한 각 보강공 길이별 축력의 변화관점에서는 큰 연관성을 보여주지 못하는 터널단면 증가율 대비 작은 증가율을 나타냈다. 또한, 각부 보강공 축력의 발생경향은 터널 단면증가율보다 보강공 마찰지지 개념 메커니즘에 따른 거동 영향성을 보여주는 것으로 분석되었다. 본 연구결과, 일정한 길이의 각부 보강공이 선정될 경우 지반불량 구간에서의 터널 단면이 다소 대단면화하여도 무리하게 각부보강공의 길이를 연장시키지 않는 것이 시공성 및 경제성을 고려한 보다 더 합리적인 방법으로 판단된다.

• 한국의류산업학회지
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• 제25권5호
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• pp.651-660
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• 2023

This study aimed to research the local production of conductive composite yarn, a source material used in textile-type electrodes and circuits. The physical properties of an internationally available conductive composite yarn were analyzed. To manufacture the conductive composite yarn, we selected one type of conductive yarn with Ag-coated polyamide of 150d 1 ply, along with two types of polyethylene terephthalate (PET) with circular and triangular cross-sections, both with 150d 1 ply. The conductive composite yarn samples were manufactured at 250, 500, 750, and 1000 turns per meter (TPM). For both conductive composite yarn samples manufactured from two types of PET filaments, the twist contraction rate of the sample with a triangular cross-section was stable. Among the samples, the tensile strength of the sample manufactured at 750 TPM was the highest at approximately 4.1gf/d; the overall linear resistance was approximately 5.0 Ω/cm, which is within the target range. It was confirmed that the triangular cross-section sample manufactured with 750 TPM had a similar linear resistance value to the advanced product despite the increase in the number of twists. In future studies, we plan tomanufacture samples by varying the twist conditions to derive the optimal conductive yarn suitable for smartwear and smart textile manufacturing conditions.

• 한국융합학회논문지
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• 제5권2호
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• pp.19-23
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• 2014

본 연구에서는 자동차 차체의 형상에 따른 차체 주위의 유동해석을 이용하여 공기 저항을 연구하였다. 입구평면에서 들어가는 공기 유동 속도가 70km/h과 100km/h인 2가지 경우이다. 승용차의 고속 주행 시(100km/h) 정속 주행(70km/h)보다 큰 항력이 나타나는 것을 알 수 있고 차체의 전방 단면적이 넓은 차가 단면적이 좁은 차보다 항력이 더 크게 나타나는 것을 알 수 있다. 본 해석 결과를 이용하여 공기 저항을 줄일 수 있는 자동차 차체의 형상 설계를 효율적으로 할 수 있다고 사료된다.

• 한국항공우주학회지
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• 제46권4호
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• pp.277-282
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• 2018

본 연구에서는 유한요소법 기반의 단면 특성치 해석 프로그램인 Ksec2d-AE의 정확성을 검증함으로써, 학부 수준의 비행체 구조해석 및 설계 시 활용가능성을 제시하고자 한다. 이를 위해 다양한 요소를 적용하여 Ksec2d-AE 로부터 계산된 단면강성계수 결과에 대한 유한요소의 수렴성을 확인하였다. 또한 Ksec2d-AE로부터 구한 단면강성계수를 상용 구조해석 프로그램인 MSC NASTRAN 으로부터 구한 강성계수와 비교하고, 주요 공학적 중심치(인장 중심, 전단 중심, 주 굽힘축)의 특성에 부합하게 구조물이 거동하는지 확인함으로써 Ksec2d-AE의 단면강성계수 및 중심치 결과를 검증하였다. 본 연구를 통하여 Ksec2d-AE 프로그램의 유용성을 확인하였다.